The present invention relates to a tape cartridge adapted for magnetic recording of information, and more particularly to an improvement in structure of a housing of the tape cartridge.
U.S. Pat. No. 3,692,255 discloses a tape cartridge including a housing in which a magnetic recording tape wound on two tape reels is driven by a flexible belt wrapped around a driving roller.
U.S. Pat. No. 4,262,860 discloses a tape cartridge of increased tape capacity which includes a rectangular housing having a significantly greater length than those of such prior art tape cartridges as U.S. Pat. No. 3,692,255.
An improved tape cartridge with increased tape capacity is described in U.S. patent application Ser. No. 799,307 filed by Aizawa et al. The tape cartridge includes a T-shaped housing having large and small area sections.
Some of such tape cartridges of increased tape capacity include a housing, a base plate on which tape packs of a magnetic recording tape are rotatably disposed, and a cover of opaque resin secured to the base plate. The cover has an opening to which a transparent panel is fitted. The transparent panel allows a sensing light emitted from a light source in a tape drive to pass therethrough so that an end of the magnetic recording tape is detected. The transparent panel is secured to the opening of the cover by means of a fastening member or in such a manner as welding, for example, high frequency welding.
However, the transparent panel often tends to suffer from distortion upon welding. The distortion causes an axis of the light to be offset from an in situ position thereof when the light passes through the distorted panel. As a result, an accurate detection of the end of the magnetic tape is disturbed. Further, since a panel mounting area of the cover is relatively small, the panel mounting operation by using the fastening member, such as a bolt and nut, requires high accuracy.
In addition, when the tape cartridge of increased tape capacity is inserted into a tape drive, a portion of the cartridge housing is seated in the tape drive and the remaining portion projects outwardly therefrom. The seated portion of the cartridge housing is subject to stress caused when a gravity center of the tape cartridge is present at the remaining portion upon insertion of the tape cartridge. Accordingly, the tape cartridge necessitates having a housing with a sufficient structural strength against the stress.
There is a need for a tape cartridge capable of preventing distortion of a transparent panel upon assembly and having a housing with an increased structural strength.